41 Effect of Biochar Supplementation in Beef Cattle Finishing Diets on Greenhouse Gas Emissions and Carcass Performance

Abstract

The objective of this experiment was to evaluate the effect of feeding biochar in a finishing diet on cattle performance, carcass quality, methane (CH₄) and carbon dioxide (CO₂) emissions. Biochar was sourced from ponderosa pine wood waste (High Plains Biochar, Laramie, WY) and was 83% C with 426 m²/g surface area. Crossbred steers (n = 128; initial BW = 480 kg ± 82 kg) were utilized in a randomized block design (blocked by BW), steers assigned randomly to pen (n = 16), and pen was assigned randomly to treatment. Two treatments were evaluated, a finisher control (CON) without biochar and the same finisher with biochar included at 1.0% of diet dry matter replacing corn (CHAR). Four pen replications per treatment were paired within BW block and rotated randomly through an emissions barn with two chambers (each treatment evaluated simultaneously) to capture average weekly emissions of CH₄ and CO₂. Pen was experimental unit and chamber was included as a fixed effect for emissions data. Dry matter intake (DMI; P < 0.01) and average daily gain (ADG; P = 0.02) were 2.4 and 5.9% lower for CHAR steers, respectively. Feed efficiency (P = 0.22) and production of CO₂ and CH₄ (P ≥ 0.60) did not differ between treatments. Methane production was numerically lower for CHAR steers when reported as g per day (1.8% lower) or g per kg of DMI (4.8% lower). Hot carcass weight tended to be lighter (P = 0.10) and calculated USDA yield grade was decreased (P = 0.02) for CHAR steers. There was no difference between treatments for LM area, USDA quality grade, or 12^th rib fat (P ≥ 0.12). In conclusion, biochar supplementation at 1.0% of diet DM reduced DMI and ADG and had no effect on CH₄ and CO₂ emissions in finishing steers.